System and methods for conversion of biohazard to municipal waste

ABSTRACT

A system for shredding medical waste, the system comprising a medical waste treating chamber ( 4 ) being an interior of an enclosure disposed within an environment which is not to be polluted, a motor ( 11   a ), a shredder ( 2 ) seated in the chamber and including a motor-driven shaft ( 17 ) and blades rotated by the shaft, the shaft ( 17 ) extending through the enclosure thereby to define an interface between the waste treating chamber ( 4 ) and the environment, and interface seal apparatus ( 101 ) preventing leakage of at least fluids from the medical waste treating chamber into the environment, via the interface.

REFERENCE TO CO-PENDING APPLICATIONS

Priority is claimed from U.S. provisional application No. 61/414,071,entitled “Biohazard Waste Disposal System and Methods Useful inConjunction Therewith” and filed 16 Nov. 2010.

FIELD OF THE INVENTION

The present invention relates generally to medical waste treatment andmore particularly to systems for sterilization of medical waste.

BACKGROUND OF THE INVENTION

Conventional technology pertaining to treatment of medical waste isdescribed in the following US patent documents inter alia: U.S. Pat. No.5,078,924; U.S. Pat. No. 5,163,375; U.S. Pat. No. 5,240,187; U.S. Pat.No. 5,236,135; U.S. Pat. No. 5,271,892; U.S. Pat. No. 5,348,235; U.S.Pat. No. 5,362,443; U.S. Pat. No. 5,387,350; U.S. Pat. No. 5,401,444;U.S. Pat. No. 5,458,072; U.S. Pat. No. 5,508,004; U.S. Pat. No.5,580,521; U.S. Pat. No. 5,639,031; U.S. Pat. No. 5,830,419; U.S. Pat.No. 5,833,922; U.S. Pat. No. 6,039,724; U.S. Pat. No. 6,113,854; U.S.Pat. No. 7,144,550; U.S. Pat. No. 7,718,120; U.S. Pat. No. 7,814,851;U.S. Pat. No. 7,815,851;

Hospitals and other facilities generate large amounts of medical wastedaily. Existing techniques for treatment of medical waste are sounsatisfactory that some health facilities in first-world countrieselect to convey only partially neutralized medical waste to poorlyregulated third-world countries for disposal, thereby causing dangerousplanet-wide pollution. Existing medical waste treating systems arecharacterized by one or more of the following: large size necessitatinga facility located at a distance from the hospital or otherwaste-generating facility rather than within the hospital; failure toachieve adequate de-contamination; generation of large volumes of wastewhich are costly to dispose of due to high per-volume disposal costs;generation of a strong, unpleasant odor; requirement for distastefulmanual handling e.g. to empty the system's chamber of processed wastewhich did not exit automatically.

ECODAS is an example of a conventional system that is said to sterilizeRegulated Medical Waste (RMW), reduce its volume by 80%, and render itscomponents unrecognizable, by shredding and direct pressurized heatedsteam all in one enclosed system achieving complete sterilization ofinfectious materials. The final treated waste is said to be harmless,unrecognizable, and safe for disposal, just like ordinary municipalwaste. Shredding is followed by superheated steam (138° C./280° F.)under high pressure (3.8 bars/55 psi) which destroys all forms ofmicrobial life.

The disclosures of all publications and patent documents mentioned inthe specification, and of the publications and patent documents citedtherein directly or indirectly, are hereby incorporated by reference.

SUMMARY OF THE INVENTION

Certain embodiments of the present invention seek to provide a systemfor treatment of medical waste in a sterilizer, which uses both vacuumand pressure, whilst cutting the waste, thereby replacing air pockets inthe chamber with steam, so as to enhance sterilization.

Certain embodiments of the present invention seek to provide a reasonfor using vacuum is to replace the air pockets in the chamber with steamso as to achieve sterilization. Typically a mechanism is provided thatcreates vacuum while cutting, while preventing small parts, glass, metaletc. entering into the sealing of the unit and destroying it.

Certain embodiments of the present invention seek to provide the abilityto filter out and drain liquids from a chamber which performssterilization and shredding, e.g. without shredded sharp matter blockingfilters, including liquids accumulating from the treatment and or liquidused to wash the unit.

Certain embodiments of the present invention seek to provide a shaftmechanism which rotates inside an external pressure tank, to preventbio-hazardous gases/liquids from being exhausted from the main wastetreating chamber through the shaft.

Certain embodiments of the present invention seek to provide a mechanismwhich protects gaskets from dirt or shredded particles e.g.metal/glass/crystals, contact with which during the cycle would damagethe gaskets.

Certain embodiments of the present invention seek to provide a compactIntegrated Sterilizer & Shredder (ISS) for on-site conversion ofbiohazard to municipal waste rapidly e.g. in as little as 25 minutes.

The ISS typically performs both size reduction and waste steamsterilization in a single vessel. The vessel is typically fitted with amotor-driven shaft, with shredding/crushing blades. Shredding the wasteensures an acceptable level of sterilization. Shredded waste istypically reduced to as little as 1/10 its original volume, withoutemitting harmful substances.

The vessel may be supported by two arms which are typically also used torotate the vessel e.g. for 2 or more of loading (45° e.g.), treatment(0° e.g.) and unloading (135° e.g.) positions. The vessel is typicallyturned by a motor, and the positions are typically indicated by magneticswitches. The unit typically includes an internal steam generator,automatically controlled by the electronic system. The vessel istypically constructed with internal sprinklers for an automatic cleaningprocess.

The vessel is typically equipped with a multipurpose shredder/crusherblade on the bottom, regulated by an electric motor which drives theknife shaft. The shaft typically connects the knife to the motor throughthe bearing housing and the sealing area. The blades are typicallymounted on the shaft and are designed to shred waste including some orall of: sharp particles, dialyzers, papers, cloth, plastic and glass.

The blades typically rotate inside the vessel to reduce the size andvolume of the waste. Typically, the blades rotate in two alternativedirections to avoid textiles and other materials becoming entangled withthe blades. Rotation in a second direction e.g. clockwise, untangles andreleases whatever may have become wound around the blades when thesewere previously rotating in a first direction e.g. counterclockwise. Forexample, software control may provide clockwise rotation for some tensto a few hundred seconds, say, 1 minute, followed by a pause of a fewseconds duration, say, a 3 sec pause, followed by a spin of typicallyapproximately the same length, say again a 1 minute spin, in theopposite, counterclockwise, direction, and so on.

The invention shown and described herein includes but is not limited tothe following embodiments:

1. A system for treatment of medical waste in a sterilizer, which usesboth vacuum and pressure, whilst cutting the waste.

2. A system according to embodiment 1 which is operative to drainliquids which accumulate from the treatment, from a chamber whichfacilitates sterilization and shredding.

3. A system according to embodiment 1 which is self-washable.

4. A system for treatment of medical waste which includes a shaftmechanism which rotates inside an external pressure tank, thereby toprevent bio-hazardous gases/liquids from being exhausted from thechamber through the shaft.

5. A system for treatment of medical waste which includes a mechanismwhich protects gaskets from entrance of dirt or shredded particles(metal/glass/crystals) which damage the gaskets during the cycle.

6. A system according to embodiment 1 wherein throughout the process,air is replaced with steam and is evacuated through a bio-filter.

7. A system according to embodiment 6 wherein sterilization withbio-burden of at least 10-6 is achieved (as opposed to disinfectors,which achieve 10-4).

8. Apparatus according to any of the above embodiments wherein thevessel is equipped with a multipurpose shredder/crusher blade on thebottom.

9. Knife apparatus which rotates above 300 RPM inside a chamber whichsterilizes medical waste, both with pressure and vacuum, whilesterilizing the air which is evacuated while the chamber is contaminated(filtering the bacteria).

10. Apparatus according to embodiment 9 wherein vacuum is used toevacuate the air from the chamber in order to penetrate into the waste(and avoid air pockets), through a bio-filter.

11. A system according to embodiment 2 wherein liquids are drained froma chamber which facilitates sterilization and shredding, through anactive filter at the bottom of the chamber.

12. A system according to embodiment 11 wherein water used for thetreatment of waste and/or for washing the chamber is sterilized andexits the chamber through the active filter, thereby to obtain drytreated waste.

13. A system for treatment of medical waste which includes a shaftmechanism which rotates inside an external pressure tank, filled with alubricant.

14. A system according to embodiment 13 wherein the pressure in the tankblocks contaminated gases/liquids from exiting from the chamber throughthe shaft (both under pressure and under vacuum).

15. A system for treatment of medical waste which includes a mechanismwhich protects the gaskets from entrance of dirt or shredded particles(metal/glass/crystals) which damages the gaskets during vacuum.

16. Apparatus according to embodiment 8 wherein the blade is regulatedby an electric motor which drives the knife shaft.

17. Apparatus wherein the motor is operative to rotate the shaft with aselectable RPM of 300-1400.

18. Apparatus according to any of the above embodiments which performson-site conversion of biohazard to municipal waste in an order ofmagnitude of 25 minutes.

19. Apparatus according to any of the above embodiments which performsboth size reduction and waste steam sterilization in a single vessel.

20. Apparatus according to any of the above embodiments which includes amotor-driven shaft, with shredding/crushing blades which can rotate intwo directions inside a vessel to reduce the size and volume of waste,thereby to provide shredding of the waste which in turn providessterilization.

21. Apparatus according to any of the above embodiments wherein aninternal steam generator (18 KW) is automatically controlled by theelectronic system and wherein the vessel is constructed with internalsprinklers for automatic cleaning.

In accordance with an aspect of the presently disclosed subject matter,there is thus provided a system for shredding medical waste, the systemcomprising a medical waste treating chamber being an interior of anenclosure disposed within an environment which is not to be polluted, amotor, a shredder seated in the chamber and typically including amotor-driven shaft and blades rotated by the shaft, the shaft extendingthrough the enclosure thereby to define an interface between the wastetreating chamber and the environment, and interface seal apparatuspreventing leakage of at least fluids from the medical waste treatingchamber into the environment, via the interface.

In accordance with an embodiment of the presently disclosed subjectmatter, there is thus further provided a system wherein the interfacehas an internal end disposed interiorly of the enclosure and an externalend disposed exteriorly of the enclosure, and wherein the interface sealapparatus comprises first and second high-speed seals sealing off theinternal and external ends of the interface respectively, such thatunless the high-speed seals have degraded, the leakage is prevented evenwhen the shredder is operating at high speed.

In accordance with an embodiment of the presently disclosed subjectmatter, there is thus yet further provided a system comprising alubricant chamber of pressurized lubricant surrounding, thereby toreduce degradation of the first and second seals and maintained at apressure which exceeds pressure in the medical waste treating chamber.

In accordance with an embodiment of the presently disclosed subjectmatter, there is thus yet further provided a system comprising apressure sensor measuring pressure in the lubricant chamber and alertingfor seal degradation if the pressure in the lubricant chamber dropsbelow a predetermined level.

In accordance with an embodiment of the presently disclosed subjectmatter, there is thus yet further provided a system wherein the medicalwaste treating chamber is generally cylindrical and has a bottom portionand wherein the shredder is seated in the bottom portion of the medicalwaste treating chamber, and wherein the motor is external to the medicalwaste treating chamber and wherein the shredder comprises a rotatingshredder and wherein the interface is generally cylindrical.

In accordance with an aspect of the presently disclosed subject matter,there is thus yet further provided a system for shredding and separatingliquids from medical waste, the system comprising a medical wastetreating chamber, a rotating shredder seated in the chamber, anapertured partition seated below the shredder and having at least oneaperture defined therewithin, thereby to partition the chamber into twocompartments communicating only via the at least one aperture, and anaperture cleaner below and fixedly associated with the rotating shredderand configured and arranged to sweep non-fluids away from the apertureas the rotating shredder rotates.

In accordance with an embodiment of the presently disclosed subjectmatter, there is thus yet further provided a system wherein the chamberis cylindrical and has an axis and wherein the aperture cleanercomprises at least one cleaning rod (which may be mounted on orintegrally formed with at least one blade of the shredder) which isdisposed at a radial distance relative to the axis and which extendsfrom the rotating shredder downward toward the apertured partition andwherein the apertured partition comprises a horizontal plate defining acentered circular track of radius r along which a plurality of aperturesare defined and along which the rod travels when the shredder isrotating, thereby to sweep non-fluids away from the plurality ofapertures.

In accordance with an embodiment of the presently disclosed subjectmatter, there is thus yet further provided a system comprising at leastone internal liquid sprinkler using sprinkled liquid to provideautomatic cleaning of the medical waste treating chamber and wherein thesprinkled liquid travels through the at least one aperture.

In accordance with an embodiment of the presently disclosed subjectmatter, there is thus yet further provided a system wherein the at leastone aperture partition has top and bottom surfaces and the at least oneaperture defines a first hole in the top surface and a second hole, inthe bottom surface, which is larger than the first hole, thereby toprevent particles from blocking the aperture.

In accordance with an embodiment of the presently disclosed subjectmatter, there is thus yet further provided a system comprising a vacuumpump operative to eliminate air pockets in the medical waste treatingchamber, and a steam generator operative to generate steam in thechamber after the air pockets have been eliminated, thereby to ensuresteam sterilization of all waste in the chamber.

In accordance with an embodiment of the presently disclosed subjectmatter, there is thus yet further provided a system which is alsooperative for shredding and separating liquids from medical waste, thesystem comprising an apertured partition seated below the shredder andhaving at least one aperture defined therewithin, thereby to partitionthe chamber into two compartments communicating only via the at leastone aperture, and an aperture cleaner below and fixedly associated withthe rotating shredder, configured and arranged to sweep non-fluids awayfrom the aperture as the rotating shredder rotates.

In accordance with an embodiment of the presently disclosed subjectmatter, there is thus yet further provided a system comprising a steamdelivering conduit leading from the steam generator to an area adjacentthe high speed seal thereby to prevent formation adjacent the at leastone seal, of a region whose pressure is low, relative to the medicalwaste treating chamber pressure, which consequently would attract sharpmedical waste particles to the seals, low pressure region formationbeing prevented by steam pressurizing the area adjacent each of the highspeed seals just prior to steam pressurization of the medical wastetreating chamber.

In accordance with an embodiment of the presently disclosed subjectmatter, there is thus yet further provided a system comprising a coneembracing the shaft encasing the high speed seals such that if thearea's pressure is equal to pressure in the medical waste treatingchamber as a whole, sharp medical waste particles do not climb up thecone, hence do not reach the seals.

In accordance with an embodiment of the presently disclosed subjectmatter, there is thus yet further provided a system wherein externalthreading is provided on the shaft such that when the shaft rotates andthe medical waste treating chamber is pressurized, sharp medical wasteparticles detrimental to the seals are propelled by the threading, awayfrom the seals.

In accordance with an embodiment of the presently disclosed subjectmatter, there is thus yet further provided a system wherein the medicalwaste treating chamber is defined by an enclosure having an opening atits top for introducing medical waste to be treated into the medicalwaste treating chamber and wherein the system includes a chamber upenderto up-end the chamber thereby to remove treated medical waste therefromvia the opening.

In accordance with an embodiment of the presently disclosed subjectmatter, there is thus yet further provided a system comprising a steamsterilizer operative to steam-sterilize contents of the medical wastetreating chamber.

In accordance with an aspect of the presently disclosed subject matter,there is thus yet further provided a method for shredding and separatingliquids from medical waste, the system comprising providing a rotatingshredder seated in a medical waste treating chamber and an aperturedpartition seated below the shredder and having at least one aperturedefined therewithin, thereby to partition the chamber into upper andlower compartments communicating only via the at least one aperture, andproviding an aperture cleaner below and fixedly associated with therotating shredder and configured and arranged to sweep non-fluids awayfrom the aperture as the rotating shredder rotates.

In accordance with an embodiment of the presently disclosed subjectmatter, there is thus yet further provided a method including washingthe chamber with a fluid which flows into the lower compartment therebyto allow selective removal of the fluid but not of non-fluid waste, fromthe chamber, via the lower compartment.

In accordance with an embodiment of the presently disclosed subjectmatter, there is thus yet further provided a method including flushing afluid through medical waste in the chamber to eliminate malodor, whereinthe fluid flows into the lower compartment thereby to allow selectiveremoval of the fluid but not of non-fluid waste, from the chamber, viathe lower compartment.

In accordance with an aspect of the presently disclosed subject matter,there is thus yet further provided a method for shredding medical waste,the method comprising providing a medical waste treating chamber beingan interior of an enclosure disposed within an environment which is notto be polluted, at least one high-speed seal to seal off the interiorfrom the environment, and providing a vacuum pump operative to eliminateair pockets in the medical waste treating chamber and a steam generatoroperative to generate steam in the chamber after the air pockets havebeen eliminated, thereby to ensure steam sterilization of all waste inthe chamber, and to generate steam adjacent the seal, thereby topressurize a region adjacent the seal so as to deter sharp particleswithin the medical waste, from approaching the seal.

A particular advantage of the apparatus of claim 1 is that high speedseals or gaskets can be used and nonetheless are only infrequently,rather than frequently, rendered inoperative hence requiringreplacement, due to contact with chemicals, dirt, and shredded metal orglass. Consequently, the shredder's blades can rotate at any suitablespeed such as perhaps a speed within the range of, say, 500-1500 rpm,such as, for example, a speed between 1000-1400 rpm, e.g. 1330 rpm,thereby allowing steam to penetrate the waste well enough to achieve acontaminant presence of less than 10_(−4); or more typically less than10_(−5) or less than 10_(−6). The embodiments referred to above, andother embodiments, are described in detail in the next section.

Any trademark occurring in the text or drawings is the property of itsowner and occurs herein merely to explain or illustrate one example ofhow an embodiment of the invention may be implemented.

The present invention may be described, merely for clarity, in terms ofterminology specific to individual products, and the like. It will beappreciated that this terminology is intended to convey generalprinciples of operation clearly and briefly, by way of example, and isnot intended to limit the scope of the invention to any particularindividual product.

Elements separately listed herein need not be distinct components andalternatively may be the same structure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 a-1 c are simplified pictorial illustrations of respectivepossible positions of an Integrated Sterilizer & Shredder (ISS) systemfor on-site conversion of biohazard to municipal waste, all constructedand operative in accordance with an embodiment of the present invention.

FIGS. 2 a-2 b, taken together, form a simplified flowchart illustrationof an example method of operation for an example ISS (steam sterilizerwith an integrated shredder), constructed and operative in accordancewith an embodiment of the present invention.

FIGS. 3 a and 3 b illustrate a knife block or “knife module” performingthe shredding functionality of the system of FIGS. 1 a-1 c, the moduleincluding blades as well as associated elements providing rotation suchas bearings and gaskets, all constructed and operative in accordancewith an embodiment of the present invention.

FIGS. 4 a-4 c are respective sectional, cut-away isometric and isometricillustrations of a bottom portion of an integrated steam sterilizationand shredding system according to an embodiment of the invention whichis particularly suited to preventing debris, particularly sharpparticles, from contacting high speed seals 101 which seal off thechamber 4, at the location in which the shaft 17 extends through thewall of the chamber 4.

FIG. 5 is a magnification of the bubble 111 a drawn in FIG. 4 b showinga conduit 111 which is typically the only communication path between thedebris in the chamber 4 and the seals 101, all being constructed andoperative in accordance with an embodiment of the present invention.

FIGS. 6 a and 6 b are respective cut-away perspective and perspectiveviews of the cone 107 of FIG. 4 b, according to an embodiment of theinvention.

FIGS. 7 a, 7 b and 7 c are respective views of the shaft 17 of FIG. 4 band external threading 190 provided thereupon according to an embodimentof the invention.

FIG. 8 is a front view of an integrated sterilizer & shredder system inaccordance with certain embodiments of the present invention, shown withopened top lid when the assembled vessel, including waste chamber, is ina vertical position, and wherein two side shafts are provided to enablerotating of the waste chamber e.g. between the positions shown in FIGS.1 a-1 c, e.g. by means of a chain sprocket.

FIGS. 9 a-9 f, 10 are respective views of components of a fluidstraining and disposal subsystem including an apertured partitionoperative to partition a waste treating chamber into two compartmentssuch that fluid collects in the lower of the two compartments andnon-fluids remain in the upper of the two compartments, all asconstructed and operative in accordance with an embodiment of thepresent invention.

FIGS. 11 a-d, 12 a-12 d, 13 a-13 e, 14 a-14 e, 15 and 17-18 areillustrations, diagrams and tables describing various embodiments of anexample ISS (steam sterilizer with an integrated shredder), fortreatment of medical waste.

FIG. 16 is a graph of pressure (dotted line) and temperature (dashedline) vs. time, useful in understanding certain embodiments of thepresent invention.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

Reference is now made to FIGS. 1 a-1 c which are simplified pictorialillustrations of respective possible positions of an IntegratedSterilizer & Shredder (ISS) system for on-site conversion of biohazardto municipal waste.

Typically, the system shown and described herein includes some or all ofthe following subsystems:

a. a medical waste treating chamber being an interior of an enclosuredisposed within an environment which is not to be polluted;

b. a shredding subsystem including, typically, a motor external to themedical waste treating chamber and a shredder seated in the chamber andincluding a motor-driven shaft and blades rotated by the shaft, theshaft extending through the enclosure thereby to define a cylindrical(e.g.) interface between the waste treating chamber and the environment;high-speed seals to seal off the interface; and a lubricant chamber ofpressurized lubricant surrounding, thereby to reduce degradation of saidfirst and second seals and maintained at a pressure which exceedspressure in the medical waste treating chamber.

Typically, a Pressure Sensor 12 a (such as, for example, a commercialpressure transducer 0 to 6 bar ABS. cat 514.99012, from Huba controlSwiss or perhaps, in certain embodiments, a Xi'an Chinastar M&C Limited,CS-PT1100A 0-6 bar pressure sensor) measures pressure in the lubricantchamber and alerts for seal degradation if the pressure in the lubricantchamber drops below a predetermined level. The first pressure sensor 12a provided for the lubricant chamber is suitably positioned, e.g. asshown in FIG. 4 c.

Typically, a steam delivering conduit leads from a steam generator to anarea adjacent each of the high speed seals thereby to prevent formationadjacent said seals, of a region whose pressure is low, relative tomedical waste treating chamber pressure, which consequently wouldattract sharp medical waste particles to said seals, low pressure regionformation being prevented by steam pressurizing the conduit just priorto steam pressurization of the medical waste treating chamber.Typically, the architecture is such that the only communication pathbetween the debris in the chamber and the seals is via a typicallyinclined conduit defined by a ramp structure, also termed herein a“cone”, such that debris needs to rise along the inclined plane definedby the cone in order to reach the seals. Typically, steam is pushedalong the conduit which is the only communication path between thedebris in the chamber and the seals to further prevent the debris fromreaching the seals. The seals are typically located in an area whosepressure is high relative to the pressure in the chamber such that apressure gradient prevents debris from reaching the seals. The shafttypically has external threading configured and arranged, e.g. relativeto the conduit which is the only communication path between the debrisin the chamber and the seals, to carry debris away from the seals as theshaft rotates.

c. a sterilization subsystem typically including a steam sterilizeroperative to steam-sterilize contents of the medical waste treatingchamber, wherein the sterilizer may include a vacuum pump operative toeliminate air pockets, which resist sterilization, in the medical wastetreating chamber; and a steam generator operative to generate steam inthe chamber after the air pockets have been eliminated, thereby toensure steam sterilization of all waste in the chamber.

d. a fluid-utilization and/or straining and disposal subsystem (FIGS. 9a-9 f, 10) including an apertured partition seated below the shredderand having at least one aperture defined therewithin, thereby topartition the chamber into two compartments communicating only via theat least one aperture; and an aperture cleaner below and fixedlyassociated with the rotating shredder and configured and arranged tosweep non-fluids away from said aperture as said rotating shredderrotates—said aperture cleaner comprises at least one cleaning rod (e.g.mounted on or integrally formed with a shredder blade) which is disposedat a radial distance r relative to the axis and which extends from saidrotating shredder downward toward said apertured partition and whereinsaid apertured partition comprises a horizontal plate defining acentered circular track of radius r along which a plurality of aperturesare defined and along which the rod travels when the shredder isrotating, thereby to sweep non-fluids away from said plurality ofapertures. The above arrangement allows flushing waste to eliminatemalodor and/or use of an internal liquid sprinkler (e.g. PNR, DDW 2294B1) for automatic cleaning of said medical waste treating chamber andwherein said sprinkled liquid travels through said at least oneaperture.

A particular advantage of the apertured partition, which is swept freeof debris as described above, is that it is effective to partition thewaste treating chamber into two compartments such that fluid collects inthe lower of the two compartments and non-fluids remain in the upper ofthe two compartments.

As shown, typically, rather than providing mill-wheels for reducing sizeof bio-hazardous matter, a shredder 2 is provided within a chamber 4which holds the bio-hazardous waste to be converted. A particularadvantage of certain embodiments is that the shredder allows the chamberto be more compact than the mill-wheels would; since mill-wheels bothoccupy space and typically require a double allocation of space for thebio-hazard, both above the wheels for pre-milled waste material andbelow the wheels for milled waste material. A motor 11 a, typicallyexternal to the chamber 4, drives the typically rotational motion of theshredder 2 blades. Once waste has been shredded, a steam generator 10supplies steam to the chamber, thereby to effectively, due to the smallsize of the shredded particles, steam-sterilize contents of the medicalwaste treating chamber.

It is appreciated that medical waste treating chamber 4 typicallycomprises an interior of an enclosure disposed within an environmentwhich is not to be polluted. Shredder 2, seated in the chamber 4,typically includes a shaft 17 driven by a motor 11 and at least oneblade assembly 18 rotated by the shaft 17. According to certainembodiments, at least one and typically more than one blade assembly 18is provided, typically including a horizontal blade 18 a and a top blade18 b, e.g. as shown in FIG. 9 a.

If the motor 11 a is external to the medical waste treating chamber 4,the shaft extends through the enclosure thereby to define a cylindrical(e.g.) interface between the waste treating chamber and the environment.

Typically, another motor, termed herein “motor 11 b” and not shown,turns the chamber 4 up-side down and then back up again. The door 6 ofthe chamber 4 may be operated by a cylinder (pneumatic system).

Typically, high-speed rotatable seals 101 are used to seal thecylindrical interface off thereby maintaining complete isolation of thewaste treating chamber's interior, relative to the environment.Typically, a chamber or tank 106 of pressurized lubricant surrounds theseals, thereby to reduce degradation thereof. The lubricant, which mayfor example comprise a suitable oil, such as but not limited to aconventional high temperature (180 degrees C.) oil lubricant, may bemaintained at a pressure which exceeds pressure in the medical wastetreating chamber.

Typically, a Pressure Sensor 12 a is provided for measuring pressure inthe lubricant chamber 106 and alerting for seal degradation if thepressure in the lubricant chamber drops below a predetermined level.

According to certain embodiments, an apertured partition (also termedherein “hole plate” or “strainer plate”) 150 (FIGS. 9 a-9 f, 10) isseated below the shredder and has at least one aperture 108 definedtherewithin, thereby to partition the chamber into two compartments, anupper compartment 160 which retains non-fluid material and a lowercompartment 170 for accumulating and drawing off liquid, whichcommunicates with the upper compartment only via the at least oneaperture. Each aperture 108 typically is generally conical inconfiguration with the wide end pointing downward, e.g. as shown.

Typically, an aperture cleaner 105 (which may for example be formed ofor mounted on a shredder blade) is disposed below and fixedly associatedwith the rotating shredder and is configured and arranged to sweepnon-fluids away from said aperture as said rotating shredder rotates.Aperture cleaner 105 comprises at least one cleaning rod, or a pair ofsuch, as shown in FIG. 10, which is disposed, e.g. held by a radial arm,at a radial distance r relative to the axis of rotation of the shredder2 and which extends downward from the shredder 2 toward said aperturedpartition 150. The apertured partition 150 typically comprises ahorizontal plate defining a centered circular track 180 of radius ralong which a plurality of apertures 126 are defined and along which therod travels when the shredder is rotating, thereby to sweep non-fluidsaway from said plurality of apertures 126.

Typically, an internal liquid sprinkler (FIG. 11 a) is provided whichuses sprinkled liquid to provide automatic cleaning of said medicalwaste treating chamber and/or to flush waste so as to eliminate malodor.The sprinkled liquid travels through said at least one aperture, therebyaccumulating in the bottom compartment for selective liquid-onlyevacuation from the chamber 4, e.g. to the local sewer system, such thatnon-liquids which are ineligible to enter the sewer system, remaininside the chamber.

Typically, vacuum is created in the chamber 4 before steam isintroduced, so as to eliminate air pockets which would compromise theefficacy of the steam sterilization. A vacuum pump 14 (e.g. Speck, VI 8)may be provided for this purpose. The steam generator 10 (e.g. such asthe example steam generator shown in FIG. 13 a) may then generate steamin the chamber, after the air pockets have been eliminated, thereby toensure steam sterilization of all waste in the chamber 4.

Typically, a cone 107 (also termed herein “ramp channel” 107) whose apexfaces upward embraces the shaft 17, encasing the high speed seals 101,such that if the pressure adjacent the seals is equal to pressure in themedical waste treating chamber as a whole, sharp medical waste particlesnonetheless do not reach said seals because they do not climb up thecone.

Typically, a steam delivering conduit leads from steam generator 10 toan area adjacent each of said high speed seals 101, e.g. the areaencased by cone 107, thereby to prevent formation adjacent said seals,of a region whose pressure is low, relative to medical waste treatingchamber pressure. If a low-pressure region were to form adjacent theseals, this region would attract sharp medical waste particles to saidseals 101. Low pressure region formation is prevented by steampressurizing the area adjacent each of said high speed seals 101 tocreate a pressure gradient sufficient to keep any sharp matter away fromthe seals, just prior to steam pressurization of the medical wastetreating chamber 4.

Steam generator 10 may comprise a Tuttnauer Israel 18 KW electricalsteam source or any other suitable steam source. Steam generator 10,vacuum pump 14, and a control box 16 which controls operation of theapparatus as a whole, are typically not location sensitive. An exampleimplementation of control box 16 is provided herein with reference toFIGS. 12 a-12 d, 17 and 18. An example implementation of steam generator10 is shown in FIG. 13 a.

A first pressure sensor 12 a may be provided for the lubricant chamberand is suitably positioned, e.g. as shown in FIG. 4 c. A second pressuresensor 12 b may be provided for the waste chamber and is suitablypositioned, e.g., as shown, on the right side on top of the holder 8 ofthe door 6 of the chamber 4; the sprinkler 13 may point downward fromthe bottom surface of the middle of the cover or door of the chamber 4.A third conventional pressure sensor termed herein “sensor 12 c” may beprovided for the steam pressure source, which may be a separate unitwhich is not integrally formed with the waste chamber.

Motor 11 a, operating the blades of the shredder 2, may for examplecomprise an SMEM, SM112M2-2B3 (5.5 kW 2p IEC 112 B3 400V 50 Hz IP55). Asuitable separate Motor e.g. SMEM, SM080A4B14 (0.55 KW 4P B14 IEC80 400V50 Hz), may move the waste chamber from one to another of itsorientations as shown in FIGS. 1 a-1 c.

An example method of operation (Cycle Sequence) for the system shown anddescribed above is now described with reference to FIG. 11 a. The methodmay include some or all of the following steps or stages, suitablyordered e.g. as follows:

Loading: waste is loaded into the chamber 4, chamber's door closes.Then, chamber rotates to process position e.g. fully vertical as shownin FIG. 1 c.

Shredding: The shredder 2 starts working with the start of the cycle atdifferent speeds, as required. The shredder 2 continues working in highspeed for 2 minutes. After this time elapses, the shredder 2 stopsworking.

Sterilization: The cycle starts with one vacuum pulse to 35 kPa, toremove the air from the chamber 4.

Heating: Steam is introduced into the chamber until sterilizationtemperature is reached, e.g. 134° C. and pressure of 312 kPa.Temperature and pressure are controlled at the required sterilizationlevel for the duration of sterilization.

A Bio Filter valve (VI in FIG. 11 a) typically operates in shoot modee.g. 3 seconds opened and 30 seconds closed, throughout thesterilization stage.

Exhaust: the shredder starts working at low speed. A top exhaust valve150 opens to reduce pressure via the bio-hazard filter of FIG. 11 a downto 150 kPa (Exhaust Press parameter). When pressure is lower than 150kPa, a fast exhaust valve opens.

Drain: Liquids and steam are rapidly exhausted from the chamber to thedrain box, until pressure equalizes atmospheric pressure. The shredder'sblades typically are operational in this stage.

Drying: vacuum is created in the chamber for 5 min. During the dryingstage, the Bio-Filter out valve VI of FIG. 11 a may operate in shootmode of 2 seconds On and 45 seconds Off. Atmospheric pressure isachieved in the chamber by controlling the compressed air to chamber andthe top exhaust valves via the bio-hazard filter, until the end of thecycle.

Unloading: typically, the chamber rotates to its unloading position(FIG. 1 b) and the waste is evacuated to the bin.

An example method of operation of the system of the present invention isshown in FIGS. 2 a-2 b. The method of FIGS. 2 a-2 b typically includessome or all of the following steps, suitably ordered e.g. as shown; itis appreciated that all parameter values are merely exemplary sincethese values may be determined by a person skilled in the art:

Step 15: Loading: waste is loaded into the chamber 4, chamber's doorcloses. Then, chamber rotates to process position e.g. fully vertical asshown in FIG. 1 c.

Step 20: Shredding: The shredder 2 starts its operation, typically atdifferent speeds, as appropriate to the application. For example, theshredder may initially operate back/forward at high speed, e.g. 3seconds forward, 3 seconds backward, for 3 minutes, and thensubsequently may operate 30 seconds forward, 30 seconds backward, againat high speed till exhaust stage (step 50 below).

Step 30: Prevacuum: The cycle starts with one vacuum pulse to 35 kPa, toremove the air from the chamber 4.

Step 40: Heating: Steam is introduced into the chamber untilsterilization temperature is reached, e.g. 134° C. and pressure of 312kPa. temperature and pressure are controlled at a suitable sterilizationlevel for the duration of sterilization. A Bio Filter valve (e.g. VI inFIG. 11 a) typically operates in shoot mode e.g. 3 seconds opened and 30seconds closed, throughout the sterilization stage.

Step 45: Sterilization: Temperature and pressure are maintained at asuitable level, e.g. 134°+4° and 312 kPa+28 kPa, for 5 minutes.

Cycle fail: If during the sterilization process, the cycle fails, thesystem goes automatically to fail mode: e.g. displays warning iconand/or text that describes the failure. The system immediately goes tospecial exhaust mode that reduces pressure and temperature via abio-filter to safety conditions.

Step 50: Exhaust: the shredder starts working at low speed. A Topexhaust valve 150 opens to reduce pressure via the bio-hazard filter(e.g. as shown in FIG. 11 a) down to 150 kPa (Exhaust Press parameter).When pressure is lower than 150 kPa, a Fast Exhaust valve opens.

Step 60: Drain: Liquids and steam are rapidly exhausted from the chamberto the drain box, until pressure equalizes atmospheric pressure. Theshredder's blades typically are operational during this stage.

Step 70: The shredder blades operate at slow speed. Pulses of pressure100 kPa (low)/115 kPa (High) in the chamber may be created with periodicoperation of the Fast Exhaust valve and Compressed air to the chambervalve for 5 minutes.

Atmospheric pressure is achieved in the chamber by controlling theCompressed air to chamber and the top Exhaust valves via the bio-hazardfilter, until the end of the cycle.

Step 80: Unloading: typically, the chamber rotates to its unloadingposition (FIG. 1 b) and the waste is evacuated to the bin.

Example

The ISS may be constructed of carbon steel and have a total height of 2m. The cylindrical (e.g.) vessel may be constructed of Stainless Steel316 L, 160 liters (150 liters net) for 16-25 Kg, with one automatichinge door. The motor is of 5.5 kW and is sufficient to rotate the shaftwith an RPM of 300-1400 for various operations. The blade is made ofhigh carbon steel with hardened cutting edges. Technical Specificationsmay be as stipulated in the table of FIG. 14 a. The example systemtypically complies with some or all of the following standards &directives:

EN 60204-1, Safety of machinery—Electrical equipment of machines—Generalrequirements;

EN 61000-6-2 Electromagnetic compatibility (EMC)—Genericstandards—Immunity for industrial environments;

EN 61000-6-4 Electromagnetic compatibility (EMC)—Genericstandards—Emission standard for industrial environments.

Machinery Directive—2006/42/EC; Pressure Equipment Directive—PED97/23/EC; EMC Directive 89/336/EEC Article 7 (1); Low Voltage EquipmentDirective 2006/95/EC.

Quality Management System Standard: ISO 9001: 2008.

FIGS. 3 a and 3 b are side and cross-sectional views of a knife blockand associated lubricant chamber, constructed and operative inaccordance with certain embodiments of the present invention.

FIGS. 4 a and 4 b are respective sectional and isometric illustrationsof a bottom portion of an integrated steam sterilization and shreddingsystem according to an embodiment of the invention which is particularlysuited to preventing debris, particularly sharp matter, from contactinghigh speed rotatable seals 101 which seal off the chamber 4, at thelocation in which the shaft 17 extends through the wall of the chamber4.

O-rings 102 provide a seal between the knife block's upper and lowerportions, preventing escape of the lubricant and reduction of pressurein the lubricant chamber. Cylindrical roller bearing 103 and deep grooveball-bearing 104 facilitate rotation of the shaft rotate about its axis;bearing 103 copes with radial stresses and bearing 104 functions as aholder bearing.

FIG. 5 is a magnification of the bubble 111 a drawn in FIG. 4 b showinga conduit 111 which is typically the only communication path between thedebris in the chamber 4 and the seals 101. FIGS. 6 a and 6 b arerespective views of the cone 107 of FIG. 4 b, according to an embodimentof the invention. FIGS. 7 a-7 c are respective views of the shaft 17 ofFIG. 4 b and external threading 190 provided thereupon according to anembodiment of the invention.

The bronze sleeve 131 generates a narrow steam-supplying channel,typically of less than 1 mm (e.g. approximately 0.5 mm) in diameter,between itself and the shaft. If the shaft rotates in a first, “forward”(e.g. clockwise) direction, together with the knives, then whenever anyparticles enter this gap, the rotation has the effect of pushing theseback into the waste chamber, thereby preserving the cleanliness of theknife block and preventing malfunction as a result of blockage.

As shown in FIGS. 3 and 4 b, 5, 6 a-6 b and 7 a-7 c inter alia, a steamdelivering path typically leads from a steam generator to an areaadjacent each of the high speed seals 101 thereby to prevent formationadjacent seals 101, of a region whose pressure is low, relative to thepressure in medical waste treating chamber 4, which consequently wouldattract sharp medical waste particles to the seals 101. Low pressureregion formation may be prevented by steam being fed along path 111, ina direction leading away from the seals, just prior to steampressurization of the medical waste treating chamber 4.

In the illustrated embodiment, the path 111 is adjacent to the shaft 17.The path 111, in the illustrated embodiment includes, proceeding in thedirection in which steam is supplied, a first horizontal path segment orconduit segment 112, a first vertical segment 113, a second horizontalsegment 115, a second vertical segment 117, a third horizontal segment119, a third vertical segment 121 (which in the illustrated embodimentcomprises a narrow channel between the shaft 17 and a typically bronzesleeve as shown), a fourth horizontal segment 123, an inclined segment125, and a fifth horizontal conduit segment or path segment 127, howeverit is appreciated that this is not intended to be limiting. It isappreciated, however, that the path 111, if provided, need not have thisparticular configuration and may be designed in any suitable manner soas to provide a narrow steam channel preserving the cleanliness of theknife block and preventing malfunction as a result of blockage, asdescribed herein, e.g. by causing a pressure gradient adjacent the sealswhich distances dirt particles from the seals by providing pressureunder the ramp channel or cone 107, as high as or higher than thepressure in waste chamber 4.

Typically, the architecture is such that the only communication pathbetween the debris in the chamber and the seals is via a typicallyinclined conduit segment 125 typically defined by a ramp structure 107,also termed herein a “cone”, such that debris needs to rise along theinclined plane defined by the segment 125 in order to reach the seals101. Typically, steam is pushed along the conduit 111 which is the onlycommunication path between the debris in the chamber 4 and the seals 101to further prevent debris from reaching the seals 101. The seals 101 aretypically located in an area, e.g. the area below the cone 107, whosepressure is high relative to the pressure in the chamber such that apressure gradient prevents debris from reaching the seals 101. As shownin FIGS. 7 a-7 c, the shaft 17 typically has external threadingconfigured and arranged, e.g. relative to the conduit 111 which is theonly communication path between the debris in the chamber and the seals,to carry debris away from the seals 101 as the shaft 17 rotates.

As shown in FIG. 6 a, the particle ramp 107 typically surrounds theshredder driving shaft 17 and shelters the seals, enabling a highpressure area to be maintained, below the particle ramp, adjacent theseals 101. The high pressure area is typically generated via a steamfeeding channel 109.

The path of the steam, which typically reaches the chamber along theinclined path segment 125, is shown by a dotted line 111 in FIG. 4 b.Typically, the steam can only reach the chamber via path 111. The steamprovided along the path 111 pushes debris away from the seals back tothe chamber 4.

The external thread 190 typically provided on the shaft 17 isadvantageous in that, when the shaft 17 is rotating so as to drive theshredder blades 18, the thread 190 propels debris if any, out of thevicinity of the seals 101, through the conical ramp. Typically,provision of an inclined exclusive path for the debris as shown, makesit difficult for the debris to elevate, and this feature in combinationwith the steam pushed into the conduit 111 makes it extremely unlikelyfor debris to reach and damage the seals 101. A plug 194 (FIG. 4 b) istypically provided to prevent leakage of the high pressure steam.

FIG. 8 is a front view of an ISS system in accordance with certainembodiments of the present invention, shown with opened top lid when theassembled vessel, including waste chamber, is in a vertical position.Typically, as shown, two side shafts are provided to enable rotating ofthe waste chamber 4 e.g. between the positions shown in FIGS. 1 a-1 c,e.g. by means of a chain sprocket.

An example Steam Sterilizer with an integrated shredder, intended fortreatment of medical waste in hospitals and clinics, is now described indetail with reference to FIGS. 11 a-11 b, 12 a-12 c, 13 a-13 b, 14 a-14d and 15.

The system includes an electrically heated bio-hazard sterilizer, whichoperates with saturated steam as a sterilizing agent, and has atemperature range of up to 138° C. (280.4° F.) and pressure up to 2.4bars (35 psi). The device includes a large steam sterilizer inaccordance with EN285, continuously operated, optionally including onlyordinary equipment without applied parts and without signal input-outputparts.

The Chamber and the Steam Generator may for example be constructed ofstainless steel and the knife of carbon steel. Heating of the wastechamber 4 may be provided by saturated steam supplied by an externalsteam generator. Metal parts in the inner surfaces are also typicallymade of stainless steel. The device's chamber is, according to oneembodiment, equipped with a single door, provided with an automaticlocking mechanism, activated by compressed air, preventing the openingof the door by a safety lock.

The ISS's operating cycles are typically user-specified. Only onegeneral program may be available: Sterilization and shredding 134° C./10Minutes, bottom (fast) exhaust, 5 minutes drying. In addition, a dynamictest program and a washing cycle are available. The service cycles, e.g.as below, may be protected by code for operation by technical staffonly:

Sterilization and shredding 134° C./10 minutes without bottom (fast)exhaust.

Sterilization 134° C./10 minutes without shredding, and without bottomexhaust (fast).

The control system of the device is typically based on state of the artmicrocomputer technology, ensuring highly reliable and safe operation.The computerized control unit typically ensures fully automaticoperation through the entire cycle; hence typically, after setting thepre-selected data and starting the operation, no further intervention isnecessary.

The selected program, the phases of the cycle and the status of themachine are typically controlled and displayed on digital readouts.

For optimal control accuracy of the sterilization parameters, the systemis equipped with temperature sensors PT100 and three pressuretransducers having the following functions:

A temperature sensor for chamber temperature

A temperature sensor for the filter's temperature

A temperature sensor for the drain box's temperature (control andmonitoring).

A pressure transducer for chamber pressure

A pressure transducer for generator pressure (control of the generatorand monitoring).

A pressure transducer in the over-pressurized sealing area for the knifeshaft (safety and monitoring).

The panel located on the front panel typically enables the operator tostart and stop the cycle.

The operator starts the machine after putting the waste into the vessel.

An example bio-hazard sterilizer and shredder is now described. It isappreciated that the particular characteristics thereof are not intendedto be limiting and any individual parameter or characteristic set outherein may be modified or omitted as suitable.

The ISS processes regulated medical waste into ordinary municipal solidwaste. This means that the resultant sterile output can be safelydisposed as regular municipal waste. The action of the shredding bladesallows steam to penetrate the waste more efficiently and eliminates thepossibility of cold spots. The resultant waste is typicallyunrecognizable and reduced by 50-80%. Post processing, the treated wasteis suitable for regular disposal.

As shown in the example piping diagram of FIG. 11 a, operation may be asfollows or any suitable variation or generalization of the following:after loading the chamber, the door automatically closes and the chamberrotates to working position (e.g. fully vertical). At this stage, onevacuum pulse of up to 35 kPa is implemented through valve no. 9, throughthe bio filter. After vacuum is created, steam is introduced through alower steam filter (valve no. 3 in FIG. 11 a), until sterilizationtemperature is achieved. The shredder blades start rotating from themoment of cycle starting.

During inflation of the chamber with steam, the bio filter valve (6) isopened, until the steam replaces the air completely. This valve releasesair through the bio-filter to the drain box. The drain box includes afloat switch and a temperature sensor, to verify that no blockage hasoccurred, and to control the temperature of water going to the drain. Incase of blockage, the exhaust is stopped and a failure indication willbe provided. During sterilization, the bio filter functions as anintegral part of the chamber being sterilized.

Compressed air is introduced through valve no. 4 (Clean filter) to cleanthe filter.

As described above, the vessel or chamber is equipped with amultipurpose shredder/crusher blade typically on the bottom, to ensureuse of the full volume of the vessel. It is regulated by an electricmotor which drives the knife shaft through a tooth belt. The shaftconnects the knife to the motor through the bearing housing and thesealing area. The motor is of 5.5 kW and is sufficient to rotate theshaft with an RPM of, say, 300-1400 which, according to certainembodiments, depends on the operations being performed. For example, (afirst and higher rotational speed, e.g. of 1330 rpm, may be provided forfast and fine shredding useful in order to eliminate large particles,whereas a second, lower rotational speed, e.g. of 300 rpm, may beprovided for slow shredding and moving of particles to allow the steamto penetrate throughout the waste. The blades are mounted on the shaftand are typically designed to shred waste such as paper, textiles,plastic and glass. The blade is typically made of high carbon steel withhardened cutting edges.

Utility connections may include an electricity connection, a mineralfree water connection, an external steam connection, a water inlet, adrain outlet and a compressed air inlet. For example: Electrical: 400V3-ph, 16 or 25 kW; External Steam: 30 KG/hr. at 6 bar; 30 l/min. coldwater, ½″ connection; Drain: 2″-4″; Compressed Air: 6 bar; HVAC:Standard computer environment, 10 air exchanges/hour in room, machineconnection to outside vent. The mineral-free water supplied to the steamgenerator, including steam supplied from boilers installed at thecustomer's site, which enters the sterilizer chamber, may have thephysical characteristics and maximum acceptable level of contaminantsindicated in the “Maximum values of contaminants in Feed water andCondensate” table of FIG. 14 b.

A reverse osmosis water purification system, e.g. as shown in FIG. 11 b,is provided according to certain embodiments, in order to improve thequality of the water used to generate steam into the device's chamber.The use of mineral-free water contributes to better performance andlonger life of the sterilizers' pipes and valves.

The reverse-osmosis water purification system typically obviates anyneed to refill water reservoirs.

A dynamic test is typically performed at intervals, e.g. at least onceevery working week, to detect leaks which under pressure may causeinfection to the operator and the environment. Operations sequence ofthis test may include some or all of the following steps, suitablyordered e.g. as shown:

Water and steam are introduced into the empty chamber at 138° C. for apreset pressure (2.4 bar), for 5 min.

The shredder is operated to create a vortex.

During periodic maintenance, or if a leak has been detected during thistest, leak detection foam may be used to detect the source of leakagesduring this test.

A suitable cleaning cycle operations sequence may include some or all ofthe following steps, suitably ordered e.g. as shown:

Water and steam are introduced into the empty chamber for 5 min; steamis introduced to the filter to clean any remaining residues.

The system holds a temperature of 60° C. in the chamber for 2 minutes,while the shredder works at high speed.

Pressurizing the chamber to 150 kPa with steam and compressed air.

Drainage of the water and residue into the drain box via the fastexhaust valve.

Adding Water for 2 minutes. The shredder's motor is stopped.

Pressurizing the chamber to 110 kPa with steam and compressed air.

Drainage of the water into the drain box via the fast exhaust valve.

FIG. 11 a is a piping diagram of a shredder of an example ISS systemconstructed and operative in accordance with an embodiment of thepresent invention. The various components of the apparatus of FIG. 11 amay, for example, be as indicated in the table of FIGS. 11 c-11 d.

FIG. 12 a is an electrical schematic diagram of the control part of anexample ISS system constructed and operative in accordance with anembodiment of the present invention. The controller may for examplecomprise a SCS2-285 or any other suitable microprocessor (e.g. as perFIG. 12 b). It is appreciated that FIG. 12 a is merely an example of anoverview of a possible control system with all inputs and outputsconnected to the control system, as well as a main power supply. FIG. 12b is a zoom-in diagram of an example controller suitable forimplementing the embodiment of FIG. 12 a.

FIGS. 12 c and 12 d are schematic diagrams of components useful inconjunction with the apparatus of FIG. 12 a; in particular, FIG. 12Cillustrates a “CPanel” including GUI operator panel with power supplyand connection to the control system of FIG. 12 b, e.g., through thecommunication connector marked “12 c” in FIG. 12B, left side, underRS232 connector. FIG. 12D illustrates a water pump valve which may beconnected to a 24 VAC power and to the control system.

FIG. 13 a is a piping diagram of a steam generator of an example ISSsystem constructed and operative in accordance with an embodiment of thepresent invention. The various components of the apparatus of FIG. 13 amay, for example, be as indicated in the table of FIG. 13 c.

FIG. 13 b is a pneumatic diagram of an example ISS system constructedand operative in accordance with an embodiment of the present invention.The various components of the apparatus of FIG. 13 b may, for example,be as indicated in the table of FIGS. 13 d-13 e.

FIG. 14 a is a table of specifications for an example ISS systemconstructed and operative in accordance with an embodiment of thepresent invention.

FIG. 14 b is a table of maximum contaminant values for an example ISSsystem constructed and operative in accordance with an embodiment of thepresent invention.

FIG. 14 c is a table of valve numbering, which is useful inunderstanding the piping diagram of FIG. 11 a.

FIG. 14 d is a table of commercially available products which areexamples of possible implementations of certain components of certainembodiments of the present invention, as indicated.

FIG. 14 e is a table of commercially available pressure sensors whichare examples of possible implementations of certain pressure sensingcomponents of certain embodiments of the present invention, asindicated.

FIG. 16 is a graph of pressure (dotted line) and temperature (dashedline) vs. time. t1-t5 are time windows, not necessarily to scale,devoted respectively to Pre-vacuum, Heating to Sterilization Temperature(Ster. Temp), Sterilization, Exhaust and Dry functionalities.

FIG. 17 is an electrical schematic diagram of an example control for theAC portion of an example ISS system constructed and operative inaccordance with an embodiment of the present invention.

FIG. 18 is an electrical schematic diagram of an example control for thesteam generator part of an example ISS system constructed and operativein accordance with an embodiment of the present invention.

The system typically allows changing parameters of the selected program.Options provided may include some or all of: Change Parameters, AnalogInputs, Digital I/O, Calibration, Manual Mode, Maintenance, and ScreenContrast.

Programmable Cycle Parameters may include some or all of:

Ster Temp 134.0 Ster Time 005.0 Dry Time 005.0 Vac Pulses 0001 End Temp090.0 SterPressAdd 012.0 ATMPressure 100.0 Pulse Vac1 070.0 Pulse VacTI0120 Pulse Press1 050.0 Pulse Vac2 030.0 Pulse Vac T2 0025 Pulse Press2090.0 Pulse Vac3 030.0 Pulse Vac T3 0025 Pulse Press3 050.0(in the above list, example values are shown).

Analog Inputs may include some or all of:

ChambPress 100.0 Gen Press 308.2 Seal Press 380.1 ElectrVacH 400.0ElectrVacL 400.0 ElectDrain 400.0 CHamb.Angle 365.9 Chamb Temp 025.0Drain Temp 025.0 ElectrGenH 400.0 ElectrGenL 400.0 Press 3 100.0 Press10 100.0 ElectrChamb 400.0 Temp 8 025.0(in the above list, example values are shown).Digital inputs may for example include some or all of:

DoorCLosesSw Gasket Touch RingOpenSw Piston2_In Piston1_In RingCloseSw2RingCLoseSw3 RingCloseSw4 StartButton StopButton Up Button Down ButtonRingCloseSw Exh.PosFixed ExhPipeFixed SafetyMainSw

Digital outputs may for example include some or all of:

Heaters Chamb.Heater Vacuum Pump Water Pump Main Locker Motor ForwardMotor Back Shred.Fast Shred.Slow DigOut5v09 Separator Water.Chamb.Steam.Chamb. Connect Exh Disrupt Exh Clean Filter

Calibration of analog inputs may be provided. In this case, typically,an ‘ANALOG INPUTS’ screen is provided on which the names and real-timevalues of all-analog inputs which the system has are displayed. Also, a‘CALIBRATION’ screen is provided which may display chamber pressure andprovide user input options such as but not limited to: ChangeGainOffset, Compute GainOffset and Restore Values. Compute Gain &Offset, for ChambPress 101.0, may for example yield the following:

AH: 300.0 RH: 300.0 AL: 100.0 RL: 100.0

The displayed lists may be browsed to select values to be calibrated.Available Calibration Operations may include:

Change Gain & Offset—Direct typing of Gain and Offset values.Compute Gain & Offset—Computing Gain and Offset by two points.Restore Values—Restore Gain and Offset values with factory defaults.

Typically, computation of calibration values for the analog inputs(temperature, pressure) is performed digitally way and not by adjustmentof trimmer pots (potentiometers). The temperature and pressure measuringcircuits are typically designed with components having a 1% precision.The temperature circuit is typically linear and has an output of 100mV÷2400 mV for a temperature range 20÷150° C. The pressure circuit isalso linear and has an output of 100 mV÷2400 for a pressure range 0 to400 kPa. The measuring at the A/D is void for values higher than 2400 mVor lower than 100 mV.

Even though the precision of the components of the circuit is 1%, theaccumulated error might reach ±5%, therefore calibration is typicallyprovided. The system is provided with non-erasable memory in which theoffset and gain data of the sensors are stored. This data may be fed tothe system through programming or through the machine.

Calibration of temperature and pressure through the machine is nowdescribed. Programming calibration procedure may be generally the same.The machine is based on the computation of offset and gain from twopoints.

FIG. 15, for example, is a graph of the actual and measured values whichmay result if the actual pressure is 100 kPa and the system measures anddisplays 90 kPa and if the actual pressure is 300 kPa and the systemmeasures and displays 310 kPa. The calibration method enables these datato be introduced into the system in order to perform automaticcorrection of the OFFSET and GAIN. The method may include:

1. Browse the calibration list using the UP and DOWN keys and select therequired:a. Read.H:—Read high value of the analog input.b. Act. H:—Actual high value of the analog input.c. Read.L:—Read low value of the analog input.d. Act. L:—Actual low value of the analog input.

Typically, a GUI enables to view system's I/O, including analog inputs,digital inputs and digital outputs e.g. as described above. Suitablestage messages may be provided. For example, exhaust stage messages mayinclude the following:

Exh Water Cooling, signifying Cooling of the chamber through the watersprinkler.

Exh Pressurizing, signifying pressurizing the chamber with compressedair before water removal.

Exh Water Remove, signifying removing water from the chamber.

Exh Finalizing, signifying that the machine is waiting for the safetypressure and temperature in the chamber.

Other status messages, some or all of which may be displayed in order tomonitor the device's status and cycle progress include:

Ready: This message is displayed during the standby stage when thedevice is ready to start a new cycle.

FAIL: This message is displayed during the standby stage whensterilization cycle fails.

Door Open: This message is displayed during the standby stage when thedoor is open.

Opening Door: This message is displayed during the standby stage whenthe door is on unlocking process.

Water Inlet: This message is displayed during the process when the waterinlets to the chamber.

Steam On: This message is displayed during the heating stage when thesystem creates pressure by steam in the chamber.

Heating to Ster.: This message is displayed during the heating stagewhen the system creates sterilization conditions.

Sterilizing: This message is displayed during the sterilization stage.

Exhaust: This message is displayed during the exhaust stage.

Dry: This message is displayed during the dry stage.

CYCLE END: This message is displayed during the standby stage when thesterilization cycle successfully ends.

TEST ENDED: The message is displayed when the dynamic test is finished.

Recommendations for waste segregation include working separately onnon-infectious waste, infectious waste, highly non-infectious waste, andsharp particle waste.

The sterilizer is equipped with two safety valves, located at thechamber and the steam generator.

The valves in FIG. 11 a are numbered according to its function, asindicated in the table of FIG. 14 c.

It is appreciated that terminology such as “mandatory”, “required”,“need” and “must” refer to implementation choices made within thecontext of a particular implementation or application describedherewithin for clarity and are not intended to be limiting since in analternative implantation, the same elements might be defined as notmandatory and not required or might even be eliminated altogether.

It is appreciated that software components of the present inventionincluding programs and data may, if desired, be implemented in ROM (readonly memory) form including CD-ROMs, EPROMs and EEPROMs, or may bestored in any other suitable typically non-transitory computer-readablemedium such as but not limited to disks of various kinds, cards ofvarious kinds and RAMs. Components described herein as software may,alternatively, be implemented wholly or partly in hardware, if desired,using conventional techniques. Conversely, components described hereinas hardware may, alternatively, be implemented wholly or partly insoftware, if desired, using conventional techniques.

The scope of the present invention is not limited to structures andfunctions specifically described herein and is also intended to includedevices which have the capacity to yield a structure, or perform afunction, described herein, such that even though users of the devicemay not use the capacity, they are if they so desire able to modify thedevice to obtain the structure or function.

Features of the present invention which are described in the context ofseparate embodiments may also be provided in combination in a singleembodiment. Conversely, features of the invention, including methodsteps, which are described for brevity in the context of a singleembodiment or in a certain order may be provided separately or in anysuitable subcombination or in a different order. “e.g.” is used hereinin the sense of a specific example which is not intended to be limiting.The term “main” and the like as used herein refer to components of thesystem, some or all of which may be provided according to certainpreferred embodiments.

It is appreciated that in the description and drawings shown anddescribed herein, functionalities described or illustrated as systemsand sub-units thereof can also be provided as methods and stepstherewithin, and functionalities described or illustrated as methods andsteps therewithin can also be provided as systems and sub-units thereof.The scale used to illustrate various elements in the drawings is merelyexemplary and/or appropriate for clarity of presentation and is notintended to be limiting.

1. A system for shredding medical waste, the system comprising: amedical waste treating chamber being an interior of an enclosuredisposed within an environment which is not to be polluted; a motor; ashredder seated in the chamber and including a motor-driven shaft andblades rotated by the shaft, the shaft extending through the enclosurethereby to define an interface between the waste treating chamber andthe environment; and interface seal apparatus preventing leakage of atleast fluids from said medical waste treating chamber into theenvironment, via the interface.
 2. A system according to claim 1 whereinsaid interface has an internal end disposed interiorly of said enclosureand an external end disposed exteriorly of said enclosure, and whereinsaid interface seal apparatus comprises: first and second high-speedseals sealing off said internal and external ends of said interfacerespectively, such that unless the high-speed seals have degraded, saidleakage is prevented even when said shredder is operating at high speed.3. A system according to claim 2 and also comprising a lubricant chamberof pressurized lubricant surrounding, thereby to reduce degradation ofsaid first and second seals and maintained at a pressure which exceedspressure in the medical waste treating chamber.
 4. A system according toclaim 3 and also comprising a pressure sensor measuring pressure in thelubricant chamber and alerting for seal degradation if the pressure inthe lubricant chamber drops below a predetermined level.
 5. A systemaccording to claim 1 wherein the medical waste treating chamber isgenerally cylindrical and has a bottom portion and wherein said shredderis seated in the bottom portion of the medical waste treating chamber,and wherein the motor is external to the medical waste treating chamberand wherein said shredder comprises a rotating shredder and wherein saidinterface is generally cylindrical.
 6. A system for shredding andseparating liquids from medical waste, the system comprising: a medicalwaste treating chamber; a rotating shredder seated in the chamber; anapertured partition seated below the shredder and having at least oneaperture defined therewithin, thereby to partition the chamber into twocompartments communicating only via the at least one aperture; and anaperture cleaner below and fixedly associated with the rotating shredderand configured and arranged to sweep non-fluids away from said apertureas said rotating shredder rotates.
 7. A system according to claim 6wherein said chamber is cylindrical and has an axis and wherein saidaperture cleaner comprises at least one cleaning rod which is disposedat a radial distance relative to the axis and which extends from saidrotating shredder downward toward said apertured partition and whereinsaid apertured partition comprises a horizontal plate defining acentered circular track of radius r along which a plurality of aperturesare defined and along which the rod travels when the shredder isrotating, thereby to sweep non-fluids away from said plurality ofapertures.
 8. A system according to claim 6 and also comprising at leastone internal liquid sprinkler using sprinkled liquid to provideautomatic cleaning of said medical waste treating chamber and whereinsaid sprinkled liquid travels through said at least one aperture.
 9. Asystem according to claim 6 wherein said at least one aperture partitionhas top and bottom surfaces and said at least one aperture defines afirst hole in said top surface and a second hole, in said bottomsurface, which is larger than said first hole, thereby to preventparticles from blocking the aperture.
 10. A system according to any ofclaim 1, 2 or 6 and also comprising: a vacuum pump operative toeliminate air pockets in the medical waste treating chamber; and a steamgenerator operative to generate steam in the chamber after the airpockets have been eliminated, thereby to ensure steam sterilization ofall waste in the chamber.
 11. A system according to claim 1 which isalso operative for shredding and separating liquids from medical waste,the system comprising: an apertured partition seated below the shredderand having at least one aperture defined therewithin, thereby topartition the chamber into two compartments communicating only via theat least one aperture; and an aperture cleaner below and fixedlyassociated with the rotating shredder, configured and arranged to sweepnon-fluids away from said aperture as said rotating shredder rotates.12. A system according to claim 11 and also comprising a steamdelivering conduit leading from the steam generator to an area adjacentsaid high speed seal thereby to prevent formation adjacent said at leastone seal, of a region whose pressure is low, relative to medical wastetreating chamber pressure, which consequently would attract sharpmedical waste particles to said seals, low pressure region formationbeing prevented by steam pressurizing the area adjacent each of saidhigh speed seals just prior to steam pressurization of the medical wastetreating chamber.
 13. A system according to claim 2 or 12 and alsocomprising a cone embracing the shaft encasing said high speed sealssuch that if said area's pressure is equal to pressure in the medicalwaste treating chamber as a whole, sharp medical waste particles do notclimb up said cone, hence do not reach said seals.
 14. A systemaccording to claim 10 or 12 wherein external threading is provided onsaid shaft such that when said shaft rotates and said medical wastetreating chamber is pressurized, sharp medical waste particlesdetrimental to said seals are propelled by said threading, away fromsaid seals.
 15. A system according to claim 6 wherein said medical wastetreating chamber is defined by an enclosure having an opening at its topfor introducing medical waste to be treated into said medical wastetreating chamber and wherein said system includes a chamber upender toup-end the chamber thereby to remove treated medical waste therefrom viasaid opening.
 16. A system according to claim 1 and also comprising asteam sterilizer operative to steam-sterilize contents of the medicalwaste treating chamber.
 17. A method for shredding and separatingliquids from medical waste, the system comprising: providing a rotatingshredder seated in a medical waste treating chamber and an aperturedpartition seated below the shredder and having at least one aperturedefined therewithin, thereby to partition the chamber into upper andlower compartments communicating only via the at least one aperture; andproviding an aperture cleaner below and fixedly associated with therotating shredder and configured and arranged to sweep non-fluids awayfrom said aperture as said rotating shredder rotates.
 18. A methodaccording to claim 17 and also including washing said chamber with afluid which flows into the lower compartment thereby to allow selectiveremoval of the fluid but not of non-fluid waste, from the chamber, viathe lower compartment.
 19. A method according to claim 17 and alsoincluding flushing a fluid through medical waste in the chamber toeliminate malodor, wherein the fluid flows into the lower compartmentthereby to allow selective removal of the fluid but not of non-fluidwaste, from the chamber, via the lower compartment.
 20. A method forshredding medical waste, the method comprising: providing a medicalwaste treating chamber being an interior of an enclosure disposed withinan environment which is not to be polluted, at least one high-speed sealto seal off the interior from the environment; and providing a vacuumpump operative to eliminate air pockets in the medical waste treatingchamber and a steam generator operative to generate steam in the chamberafter the air pockets have been eliminated, thereby to ensure steamsterilization of all waste in the chamber, and to generate steamadjacent the seal, thereby to pressurize a region adjacent the seal soas to deter sharp particles within the medical waste, from approachingthe seal.